Briquette and process for making same



Patented May 31, 1932 UNITED STATES PATENT OFFICE GUSTAV KOMAREK, OFCHICAGO, ILLINOIS, ASSIGNOR TO IBERWIN'D FUEL COMPANY OF DELAWARE, OFCHICAGO, ILLINOIS, A CORPORATION OF- DELAWARE IBBIQUETTE AND PROCESS FORMAKING SAME No Drawing. Application filed June 20,

The present invention relates to fuel briquettes, and has as an objectto provide a briquette of improved composition and a new and improvedprocess for the manufacture of briquettes.

An object of the invention is to reduce the formation of dust in themanufacture and handling of the briquettes, and also to improve thebriquette for combustion purposes, more particularly by reducing thesmoke given ofli' during combustion.

Briquettes are ordinarily made from finely divided carbonaceousmaterial, such as anthracite or bituminous coal, coke fines, orpetroleum coke, and an improved briquette composition involvin the useof petroleum coke and other materlal of low volatile con- 1 tent, suchas coke fines, is disclosed in my Patent 1,7 96,465, Mar. 17, 1931.

Briquettes of these compositions have one fault in common with coal orcoke, namely, the dust which is produced by the abrasion set up inhandling. Briquette dust is particularly objectionable, due to the lossof combustible material, and furthermore, because of the binder whichmakes the dust sticky, and, therefore, more objectionable than dust ofordinary coal or coke.

It is, of course, old and well known to utilize various chemicals forallaying coal dust, and their use is extensively treated in Bulletin 20of the Bureau of Mines, (Government Printing Oifice, 1911) entitled TheExplosibility of Coal Dust. However, so far as I am aware, the use ofdeliquescent materials 'has heretofore never been extended tobriquettes. Their use in briquette manufacture is attended withproblems, such as the deterioration of the briquette by the chemicals,which is more serious than any deterioration due to. dust formation.

Briquettes ordinarily comprise the combustible 'mass, such as coal,coke, or a combination of these, and a binder. Binders are of twogeneral classes, namely, (1) those impervious to moisture, such as coaltar pitch and asphalt, and (2) those susceptible to moisture andsomewhat hygroscopic, such as sulphite liquor and starch. Y c

When 'either class of binder is used it has 1929. Serial No. 372,545.

onsequently, old and well known processes heretofore employed forallaying coal dust are not practicable, since the heating and drying ofthecoal to remove moisture, would at the same time remoil e thehygroscopic material applied to the coa Furthermore, the inclusion of .adeliquescent material in the briquette would, naturally, be regarded asobjectionable, for the reason that its hygroscopic action woulddeteriorate the binder, and, by impairing the adhesive qualities of thelatter, break down the briquette. For these reasons any hygroscopicallyactive material heretofore used in the briquettes have been employed forother than hygroscopic action and have been chemically neutralized, thuseliminating any tendency to absorb moisture.

I have discovered that it is possible, and desirable, to use inbriquettes a deliquescent material, and particularl a deliquescent salt,such as calcium chloride CaCl magnesium chloride (MgCI or a materialsuch as p'otassium carbonate (K CO These materials by their hygroscopicaction improve the briquette, and not only prevent the formation ofdust, but also slow down combustion, thereby reducing the amount .ofsmoke given off.

This retardation of combustion renders neceshygroscopically active. Thisphase of my invention involves in its applicationi to briuettemanufacture particular attention to t e nature of the binder employed.If, in

the briquette, a binder or other material is 1 used, which tends tocombine or react chemically with the deliquescent material, then asufficient amount of such deliquescent materialmust be used over andabove that. part which combines with or is neutralized by the binder orany other ingredient, in order that salt, the latter should be used insuch an or mixing'operation difi'uses the deliquescent amount, andapplied in such a way, as to be free for hygroscopic action. Also itmust be employed in the manufacturing process in such a way as not tobreak down the adhesion of the combustible particles produced by thebinder. This may be accomplished by controlling the amount ofdeliquescent material used, and also by following my improved process,which involves varying the mode of including the deliquescent materialor salt in the briquette.

In the manufacture of practically all briquettes the moisture is largelyremoved from the combustible mass of carbonaceous material before it ismixed with a binder. This mass consists of finely divided material, suchas anthracite or bituminous coal; The carbonaceous material is thenmixed with a suitable binder, and to this mixture the deliquescentmaterial may be added in dry form, particularly when steam is introducedduring the kneading or mixing operation. Such-material as deliquescentsalts of the magnesium chloride group,'or of the calcium chloride.

group, have been found very satisfactory.

The steam introduced during the kneading salt through the mass or mixand the briquettes subsequently formed or molded ther'efrom have thesalt or' other deliquescent material distributed therethrough. Thisprocesshas been found to be very satisfactory when either asphalt, orcoal tar pitch binders have been used, and even when a secondary binderis employed, such as sulphite liquor,

starch or bentonite.

calcium or magnesium chloride, or both, is

used, for the reason that the moisture content of. the solution lessensthe adhesive effect of the binder. When the deliquescent salt isintrodueed' before the briquette is molded, it is preferable to utilizethe. material in dry form, particularly if steam or other agents whichwill dilfuse the material through the mass are employed during thekneading operation.

After the briquette has been formed, or as it is formed, a deliquescentmaterial may be applied to its surface, for instance, by maintainingmoist or saturated with the solution, the forming rolls or molds of theapparatus. Such a method has been found useful either in lieu of, or inaddition to, the introduction of dry deliquescent material in themixture. This procedure thoroughly impregnates the surfaces of thebriquettes, and it is found there is a penetration for a suflicientdepth, thereby rendering the exterior of the briquette hygroscopic.

I have observed that this method, when employed for the application ofdeliquescent salts, afi'ords good protection and improves the surfacesof the briquettes not only by allaying dust, but also by slowing downcombustion. This slowing of combustion is probably due to an increasedmoisture content; it

renders necessary higher temperatures before there can evolve thesmoke-producing volatile gases contained in the binder.

As to the percentage of deliquescent material to be included, these willnecessarily vary,

because of the different types of combustible carbonaceous materialsemployed, and also because of the different binders utilized inbriquette manufacture- If the briquette includes either as a binder orfor other purposes, a material which is chemically active relativeto thedeliquescent material orsalt, then, of course, it is necessary toutilize an amount of the latter suflicient to leave in the completed briuette a free or available portion of the deliquescent material, i. e., aportion over and above that neutralized by the reactive element in themix, in order to produce a hygroscopic action.

However, it is preferable to utilize the binder which ischemically'inactive or inert relative to the deliquescent material andto guard against the inclusion of in redients which react chemicallywith the deliquescent material, and thus counteract its hygroscopicaction. A binder such as coal tar pitch or asphalt is of this nature.

- With briquettes of this composition, i. e., those which include aninactive or inert binder and no other elements which chemically modifythe deliquescent salt, one percent 1%) of calcium chloride, magnesiumchloride, other deliquescent salt will suflice as a deliquescentmaterial content, and will aiford the desired hygroscopic action. Thlscontent may be obtained by introducmg dry or crystal magnesium orcalcium chloride into the mixture, or by surface impregnation of theformed briquette. Orboth modes of application may be adopted.

ThlS amount of calcium chloride 1%) will of the binder, although when abinder such as sulph ite liquor, which has an aflinity for moisture andis itself hygroscopic is employed, it

will be found preferably to utilize the surface the harder coals, whichare not so dusty.

the completed briquette is a deliquescentma erable that the deliquescentmaterial should When the allaying of dust is the only consideration, andthe surface impregnatlon method is followed, it will be satisfactory 1fabout one-eight to 1 quarter percent of terial; but where it is desiredto slow combustion and reduce the evolution of smoke during burning, thecontent of deliquescent material should be higher, and then it is prefbeintroduced into the body of the briquette by other means than surfaceimpregnation, either in addition to the surface impregnation or in lieuthereof. It has been found that for improving the combustion andreducingsmoke given off, the content of deliquescent materials of thenature of calcium chloride and magnesium chloride should be in theneighborhood of one percent (1%).

The following will serve as suitable examples of compositions which havebeen found satisfactory I 1 Per cent Coal 93 Asphalt 6 Calcium ormagnesium chloride 1 2 Coal 92 Asphalt 4.- Sulphite liquor 3 Calcium, ormagnesium chloride 1 3 Coal 93 Asphalt 5 Bentonite 1 Calcium ormagnesium chloride 1 4 I Coal 93 Coal tar pitch 6 Calcium or magnesiumchloride 1' C031 93 Goal tar pitch 5 Bentonite 1 Calcium or magnesiumchloride 1 In the above compositions the deliquescent salt has beenincluded in dry form, and in lieu thereof by surface impregnation. Alsoboth methods of introducting the deliquescent material have beenutilized. That is to say, a portion of the salt has been introduced indry form and the remainder by impregnating the surface of the formedbriquette by an aqueous solution.

It will be understod thatboth magnesium and calcium chloride may-be usedat the same time, if desired. The invention is characterized by the useof a coal which has not been treated with hygroscopic material, and fromwhich, on the contrary, the moisture has been removed by drying andheating. Moreover, the invention contemplates the mixing of the coal orother carbonaceous mass with the binder before the deliquescent materialisintroduced, so that the carbonaceous material may be subjected to thebinder and coated therewith before it is subjected to moisture resultingfrom the hygroscopic material.

The coal particles are thus treated thoroughly with the binder, andsince they are free from moisture, the binder may cause adhesion of thevarious particles, more effectively than if the moisture content of thecoal were high, or artificially raised by applying the deliquescentmaterial thereto before the subjection of the coal to the binder.

In all of the various methods utilized there should be free or availablematerial in the formed briquette. In some processes which involve thebaking or coking of the molded briquette, it may be found desirable toimpregnate the surface with the deliquescent material in solution afterthe coking operation.

Obviously, the invention is not limited to the details above set forth,and such variations may be made therein as come'within the scope of thefollowing claims which define the more essential features.

I claim:

1. The method of preparing fuel briquettes which comprises preliminarilydrying a carbonaceous material, mixing therewith a binder, addingthereto a deliquescent salt in dry form and in sufiicient quantity to behygroscopically active, and molding the mixture. i

2. The method of preparing fuel briquettes which comprises prelimlnarilydrying a carbonaceous material, mixing therewith a' binder, addingthereto a deliquescent salt in dry form andin sufficient quantity to behygroscopically active, kneading the mixture, diffusing the salt throughthe mass by means of steam and then molding the briquette. i

3. The method of preparing fuel briquettes which comprises preliminarilydrying a carbonaceous material in finely divided form, mixing the finelydivided carbonaceous material with a binder, adding thereto adeliquescent salt in dry form and in sufiicient quantity to be free,whereby to exert a hygroscopic action, kneading the mixture, diffusingthe salt by means of steam throughout the mass, molding the briquetteand applying a deliquescent salt 'in solution to the surface of themolded briquette.

4. The process of preparing fuel briquettes which comprisespreliminarily drying a carbonaceous material in finely divid ed form,mixing the finely divided carbonaceous material, a deliquescent salt anda binder substantially chemically inactive rel ative to the material,whereby the latter may be hygroscopic-ally active, molding thebriquettes and applying a deliquescent salt in solution to the surfaceof the molded briquette.

5. A. fuel briquette. comprising finely divided substantially drycombustible car-- bonaceous material, tabinder, and a deliquescent saltin dry form in sufficient quantity to be hyiroscopically active.

6. briquette comprising carbonaceous material, a binder, and adeliquescent salt coating the surface of the briquette andpencrating-the briquette and extending below the surface thereof, saiddeliquescent salt being present in suflicient quantity to behygroscopically active.

In testimony whereof I have hereunto set my hand.

GUSTAV KOMAREK.

